India-rubber spring



, 2 Sheets-Sheet l, W. F CONVERSE,

Carriage-Spring;

No. 12,738. Patented Apr 17, 1855 I f l To all whom timely cont/era? vmcmnsmn rxr F WILLIAM F GONVERSE, OF HARRISON, OHIO.

re it known thatl, WM. FL CONVERSE,

of Harrison, Hamiltoncounty, Ohio, have inventedjnew and useful Improvements in India-Rubber Springs, and I dohereby dehclare the followingtobe a full, clear, and exact 3 description thereof, reference 1 being My improvements have for their objects, 1, so incasing a cylindrical or spheroidal blQCk y. ofiindia rubber, asthat an equal or 1 nearly equal resilient force is exerted from 1 every part of its perimeter," and in (111'60- tionsradiating from acommon center, at or near the axis of: themblock, the surface of s i the block beingwin every condition of its action equally and completely incased. Such arrangement of theinclosing device is I found to result in a more complete, efiective and enduring resilient action than where a portion is allowed to expand while another ;portioncontracts. 2, facility for any desired extension of the range of action.-

3,regulation; of the resilient force.

In the annexed' drawings Figure I is a a perspective view. Fig, 2 is a transverse sectron and Fig. 3an ax al sectlon of oneform of my improvement.

resilient force of theI rubber. Washers (e),

(w) is a blockof indiarubber ofcylindrical formand of about equal length and diameter and notched (b)alongwone side, to admit the hook of the toggle hereafter described.

' Thisblock is traversedflalong its axis by a bolt (0) furnished at one or "both ends with nuts (p), whichkholdand press against the 1 ends of, the block, circular disks or heads which confine theblock in the direction of its axis, and by being screwed more or less tight afford" a means of regulating the placed between the heads and the ends of i the block, alsoalford'a means of adjustment, and may be introduced of different thicknesses and number, accordingto the degree oftensiondesiredfor. the rubber.

Th heads, when once adjusted to their proper: position remain ystationary, their oflicebeingfitoopposethe expansion of the rubber block in the {longitudinal direction,

when under the actionof the compressing forces, which, insteadjof being applied longitudin ally in the lusualway, are made to a had tothe annexed drawings, making part of thisspecification.

INDIA-RUBBER srnnve.

; Specification of LettersIEatent No. 12,738, dated April 1'7, 1855.

act exclusively in. a, radial direction, converging from all sides to a common line at or near the axis of the block. This radial action toward a central line is produced by the following mechanism:

i (f, 9,) is a yielding case, sheath or strap, consisting of a series of hooked and bent plates or cylindrical segments (f) united by links or bridles (g). The curve given both to segments and links, is such as to adapt them to the cylindrical surface of the block. The two extremities of thisstrap are linked to a pairof levers (i z") near to their comnotch of the block. The ends, may beheld together within the block by a hook (j) on one lever which retains within its concavity the V edge (h), of the other lever.

or free extremities of the levers, is to draw together the ends of the strap, and thus to contract it around the block.

The convex surface or head of the hook, is suficiently expanded to hold back and press toward the center ofthe rubber, the portion not confined by the strap. By these means all parts of the rubber are pressed toward a central line, at or near and parallel with the axis of the cylinder, the resistance of the rubber augmenting in every direction, as the levers approach the rubber not being permitted to expand in one direction, while contracting in another, and the block being in every condition of action and inaction pressed equally on all parts of its surface, and constantly preserving the cylindrical form, under all circumstances. Thus is remedied a defectinherent in allindia rubtensional or compressible force wheretheentire surface is not supported the defect traction or, expansion) of the middle por-' tions. j v

i It will be seen that in the most extended jpositionof the levers,-they act with a less powerful leverage than in the compressed position, but have of course a far less "resila ient force to overcome than when brought closer together. In order however to en promptas maybe desired, the concave surber springs, wherether subjected toan ex-' consisting in the undue disturbance (conable theinitiatory action to be made asmon fulcrum or point of contact, within the a The effect of compressing together the other faces'ofthe segments are grooved at right angles with the axis, so that the opposing resilience of the block does not react against the entire surface of the strap until all the grooves are filled. The amount of action of these grooves will depend on their form, depth, and number which may be varied to suit the object of the constructor. Another beneficial action of these grooves is that their ridges serve as so many heads, to act in concert with the external ones in equalizing the longitudinal strain of the block when under a heavy pressure. The form of the block may in some cases, be slightly varied from the cylindrical one, as for instance it may be prolately spheroidal or even prismatical. The range of the levers may be one half of their length or less according to circumstances. Only a small portion is here shown of the length of lever intended in actual use.

The levers themselves may be forged or cast of the whole length required for use, or if made shorter, as in the illustration may be bolted, welded, or riveted to suitable bars or plates. These bars or plates, not being required to spring should have their greatest width in the direction of the motion, so as to combine lightness with strength; they may be made of steel, wrought iron or malleable cast iron, and may be formed to suit the circumstances of their application. If the metallic parts are of malleable or wrought iron, the working surfaces may be case hardened. This plan of spring is applicable to carriages, mortising machines, saddle trees and other objects to which springs are applied.

For carriages, one short bar may be attached to the holster, and a longer one be made to rest upon the axle bed or head block as the case may beor in any other mode that the nature of the vehicle or judgment of the manufacturer may indicate.

A spring thus formed will be found to be more cheaply constructed, more enduring and reliable, not subject to become impaired in its effective force or brittle with use, and by the application of the described levers and toggle or fulcrum in this connection, the spring can be made to act with a range and efliciency equal to the best steel spring; and should it be desired at any time to apply a diiferent size or quality of rubber, a new block can be inserted at the cost of a few cents. In no other plan of india rubber spring known to me, is the action effected by a pressure from all parts of the perimeter toward an axial line by contracting the case radially upon the rubber. Where desired, the range of the levers may be limited by a stirrup (is) as represented or by a headed pin or by flanges projecting from the'heads.

I prefer a jointed case such as described, to wires or to a pliable steel or iron hand, because there is no strain of the cohesive power of the metal by bending. Neither are cords of gut or hemp so desirable for permanent purposes as metal, because they are liable to stretch and to become brittle with age.

The rubber used may be of the vulcanized kind employed for the springs of railroad cars.

Fig. 4 represents a modification of my invention in which the jointed strap is replaced by strong cords, gut, or wires (6).

Figs. 5 and 6 represent by transverse section and side view an arrangement of interlocking fingers q) bent to a cylindrical form to fit the block, and attached eccentrically to the confining pin (0)-the flanges or levers (i i) in the illustration being so disposed and attached as to adapt the device to closing doors.

In Fig. 7 the oflice of the strap is served by a steel band (m).

Fig. 8 exhibits the application of a compressing cord in place of the jointed strap, and may be used for a door spring or like purpose where the action is efiected by closing the levers together.

I regard the compound lever and the adjustable heads as represented, as valuable and novel but not absolutely essential adjuncts to my original device. In the maj ority of the many purposes to which the invention may be applied, one end of the strap willinstead of being united to a leverbe attached directly either to the bearing or to the moving object itself. A probably very prevalent construction, for a great variety of light purposes, (such as door springs, furniture cushions, &c.) will be, to forge or cast the heads solid to a single lever; a simple flangefor direct attachment to the objectbeing substituted for the other lever; in which case the central bolt and the adjusting nuts may be dispensed with.

For mortising machines, embossing presses, carriage springs, and other purposes requiring great resilient power, some convenient means of adjustment will be desirable, and may be effected either in the man ner illustrated, or by metallic disks, or by keys applied either to the heads or to the strap connections.

The elastic block may be composed of caout-choucvulcanized or otherwiseor of a suitable mixture of caoutchouc and guttapercha; and from the yielding nature of such materials, a variety of shapes will serve with nearly equal efficiency'; providing the capacity of the block is such as to exactly fill the cavity of the strap when merely contracted to its normal or inactive condition.

I am aware that springs of india rubber and other similar materials have been completely confined in cylindrical and other unyielding cases. Such an arrangement therefore I do not claim; but

sire to secure by Letters Patent is The method of confining a cylindrical pr 1 prismatic block of india' rubber at all points of its surface, by means of a jointed or otherwise flexiblecylindrical strap, connected to double levers or their equiyalents, for applyradially upon the inclosed rubber; I likewise plates for securing the rnbber from lateral i WhatI do claim asmy inventionand deing the ccmpressing strain, convergently or claim in this connection adjilstable end F. CONVERSE. Witnesses:

GEO. H. KNIGHT, BEN I. HORTON. 

